Encapsulated cure systems
View Patent ↗Encapsulated cure systems are provided wherein a curative is incorporated into a solid or semi-solid carrier material whereby mere fracturing or failure of the capsule wall encapsulating such cure systems will not provide for or allow sufficient release of the curative. Also provided are adhesive systems incorporating said encapsulated cure systems.
1. An encapsulated cure system for curable compositions comprising:
a) an in-situ formed carrier material,
b) a curative contained in said carrier material, and
c) a polymer capsule encasing said carrier material;
wherein the in-situ formed carrier material is a natural or synthetic material or composition that is substantially non-flowing in the absence of external forces, elevated temperatures or both and is formed by the action of a curative with or on a precursor composition for said carrier material following the addition of the curative (b) to said precursor composition wherein either (i) the curative for the in-situ formed carrier material is different from and in addition to the curative (b) contained in said carrier material or (ii) the curative for the in-situ polymerized carrier material is the same as the curative (b) and the amount of said curative is at least 1.6 weight percent prior to the in-situ polymerization of the carrier material and at least 0.1 weight percent following the in-situ polymerization of the carrier material: weight percent being based on the weight of the carrier material, said curative for the carrier precursor composition being soluble or miscible in said precursor composition.
2. The encapsulated cure system of claim 1 wherein the carrier material is (a) of a soft, putty-like or gel-like character or (b) a solid or semi-solid that is (i) soluble in a liquid curable matrix component of the curable composition with which they are to be used, (ii) softened by a liquid curable matrix component of the curable composition with which they are to be used, (iii) softened by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (iv) softened by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (v) is softened by the method or process by which the curative (b) is to be made available to other components of the curable composition with which they are to be used, (vi) rendered flowable by a liquid curable matrix component of the curable composition with which they are to be used, (vii) rendered flowable by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (viii) rendered flowable by the environmental conditions under which the curable composition is cured or polymerized, (ix) is rendered flowable by the method or process by which the curative (b) is to be made available to other components of the curable composition with which they are to be used.
3. The encapsulated cure system of claim 2 wherein the carrier material is of a soft putty-like or gel-like character and the precursor composition comprises a thixotropic or thickened composition of monomers, oligomers or pre-polymers, or a combination thereof, which composition is substantially non-reactive with the curative (b) in the encapsulated state.
4. The encapsulated cure system of claim 3 wherein the carrier material includes or comprises one or more thixotropic agents or one or more thixotropic or non-thixotropic gelling or thickening agents that are generated in-situ or act latently concurrent with or following encapsulation of the carrier material.
5. The encapsulated cure system of claim 2 wherein the carrier material is selected from the group consisting of hot melts, pressure sensitive adhesives, rubber materials, elastomer/tackifier compositions, a polymer whose Tg is less than 35° C., semi-solid and solid resins, starches and starch-based polymers, hydrogels, low temperature waxes and a thickened or gel-like mass of one or more monomers, oligomers, prepolymers or combinations thereof.
6. The encapsulated cure system of claim 2 wherein the carrier material is an adhesive or has latent adhesive properties.
7. The encapsulated cure system of claim 1 wherein the carrier material does not flow or deform except when subjected to forces of at least 1 psi.
8. The encapsulated cure system of claim 1 wherein the curative (b) is dispersed in the carrier.
9. The encapsulated cure system of claim 1 wherein the curative (b) is dissolved in the precursor composition.
10. The encapsulated cure system of claim 9 wherein the curative (b) and the precursor composition are miscible with one another.
11. The encapsulated cure system of claim 1 wherein the capsule wall is substantially impermeable to the curative (b).
12. The encapsulated cure system of claim 1 wherein the curative (b) is substantially non-migratory in said carrier.
13. The encapsulated cure system of claim 1 wherein the curative (b) following formation of the in-situ polymerized carrier material amounts to from about 0.1 wt. percent to about 25 wt. percent of the carrier.
14. The encapsulated cure system of claim 1 wherein the curative (b) is a cross-linking agent or hardener and the amount of the curative is from about 2 wt. percent to about 50 wt. percent of the carrier.
15. The encapsulated cure system of claim 1 wherein the polymer capsule comprises from about 0.8 wt. percent to about 25 wt. percent of the encapsulated cure system.
16. The encapsulated cure system of claim 1 wherein the precursor composition comprises one or more polymerizable monomers, oligomers, prepolymers or combinations thereof.
17. An encapsulated cure system comprising
a) an in-situ formed carrier material,
b) a curative contained in said carrier material, and
c) a polymer capsule encasing said carrier material;
wherein the in-situ formed carrier material is a natural or synthetic material or composition that is substantially non-flowing in the absence of external forces, elevated temperatures or both, and is formed concurrent with or subsequent to encapsulation thereof from a liquid carrier precursor composition having mixed, dispersed or dissolved therein the curative (b); said in-situ formed carrier material formed by the action of a curative with or on said liquid carrier precursor composition following the addition of the curative (b) to said precursor composition wherein either (i) the curative for the in-situ formed carrier material is different from and in addition to the curative (b) contained in said carrier material or (ii) the curative for the in-situ polymerized carrier material is the same as the curative (b) and the amount of said curative is at least 1.6 weight percent prior to the in-situ polymerization of the carrier material and at least 0.1 weight percent following the in-situ polymerization of the carrier material: weight percent being based on the weight of the carrier material, said curative for the carrier precursor composition being soluble or miscible in said precursor composition.
18. The encapsulated cure system of claim 17 wherein the curative (b) is miscible with the liquid carrier precursor composition.
19. The encapsulated cure system of claim 17 wherein the carrier material is (a) of a soft, putty-like or gel-like character or (b) a solid or semi-solid that is (i) soluble in a liquid curable matrix component of the curable composition with which they are to be used, (ii) softened by a liquid curable matrix component of the curable composition with which they are to be used, (iii) softened by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (iv) softened by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (v) is softened by the method or process by which the curative (b) is to be made available to other components of the curable composition with which they are to be used, (vi) rendered flowable by a liquid curable matrix component of the curable composition with which they are to be used, (vii) rendered flowable by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (viii) rendered flowable by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (ix) is rendered flowable by the method or process by which the curative (b) is to be made available to other components of the curable composition with which they are to be used.
20. The encapsulated cure system of claim 17 wherein the liquid carrier precursor composition comprises one or more monomers, oligomers, prepolymers or combinations thereof which, in the absence of other curatives or conditions, is substantially non-reactive with the curative (b).
21. The encapsulated cure system of claim 17 wherein the liquid carrier precursor composition comprises one or more monomers, oligomers, prepolymers or combinations thereof which is reactive with the curative (b) provided that the amount of curative (b) in the precursor composition exceeds that which is needed to effect cure or polymerization of the precursor composition.
22. The encapsulated cure system of claim 17 wherein the precursor composition comprises one or more polymerizable monomers, oligomers, prepolymers or combinations thereof.
23. The encapsulated cure system of claim 17 wherein the curative (b) is substantially non-migratory in said carrier.
24. The encapsulated cure system of claim 17 wherein the polymer capsule comprises from about 0.8 wt. percent to about 25 wt. percent of the encapsulated cure system.
25. A curable composition comprising one or more liquid polymerizable monomers, oligomers, prepolymers or a combination thereof and an encapsulated cure system said encapsulated cure system comprising:
a) an in-situ formed carrier material,
b) an effective amount of a curative contained in said carrier material suitable for effecting cure of the aforementioned liquid polymerizable material, and
c) a polymer capsule encasing said carrier material wherein the in-situ formed carrier material is a natural or synthetic material or composition that is substantially non-flowing in the absence of external forces, elevated temperatures or both and is formed by the action of a curative with or on a precursor composition for said carrier material following the addition of the curative (b) to said precursor composition wherein either (i) the curative for the in-situ formed carrier material is different from and in addition to the curative (b) contained in said carrier material or (ii) the curative for the in-situ polymerized carrier material is the same as the curative (b) and the amount of said curative is at least 1.6 weight percent prior to the in-situ polymerization of the carrier material and at least 0.1 weight percent following the in-situ polymerization of the carrier material: weight percent being based on the weight of the carrier material, said curative for the carrier precursor composition being soluble or miscible in said precursor composition.
26. The encapsulated cure system of claim 25 wherein the carrier material is (a) of a soft, putty-like or gel-like character or (b) a solid or semi-solid that is (i) soluble in a liquid curable matrix component of the curable composition with which they are to be used, (ii) softened by a liquid curable matrix component of the curable composition with which they are to be used, (iii) softened by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (iv) softened by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (v) is softened by the method or process by which the curative (b) is to be made available to other components of the curable composition with which they are to be used, (vi) rendered flowable by a liquid curable matrix component of the curable composition with which they are to be used, (vii) rendered flowable by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (viii) rendered flowable by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (ix) is rendered flowable by the method or process by which the curative (b) is to be made available to other components of the curable composition with which they are to be used.
27. The curable composition of claim 25 further comprising a thickening agent or a thixotrope so that the encapsulated curative (b) will remain suspended therein for a sufficient period of time to allow the applicator to finish the application of the adhesive to the whole of the parts to be bonded.
28. The curable composition of claim 25 wherein the carrier material is of a soft putty-like or gel-like character and the precursor composition comprises a thixotropic or thickened composition of monomers, oligomers or pre-polymers, or a combination thereof, which composition is substantially non-reactive with the curative (b) in the encapsulated state.
29. The curable composition of claim 25 wherein the carrier material includes or comprises one or more thixotropic agents or one or more thixotropic or non-thixotropic gelling or thickening agents that are generated in-situ or act latently concurrent with or following encapsulation of the carrier material.
30. The curable composition of claim 25 wherein the carrier material is selected from the group consisting of hot melts, pressure sensitive adhesives, rubber materials, elastomer/tackifier compositions, a polymer whose Tg is less than 35° C, semi-solid and solid resins, starches and starch-based polymers, hydrogels, low temperature waxes and a thickened or gel-like mass of one or more monomers, oligomers, prepolymers or combinations thereof.
31. The curable composition of claim 25 wherein the carrier material is an adhesive or has latent adhesive properties.
32. The curable composition of claim 25 wherein the carrier material does not flow or deform except when subjected to forces of at least 1 psi.
33. The curable composition of claim 25 wherein the liquid polymerizable material is selected from the group consisting of monomers, oligomers and/or prepolymers that undergo vinyl polymerization; unsaturated polyesters; urethanes; epoxy resins; polysulfides; isocyanates; silicones; polyethers, polyurethanes and polyolefins having silanol moieties capable of undergoing silanol condensation or hydrosilation reactions; and phenoxy resins.
34. The encapsulated cure system of claim 25 wherein the precursor composition comprises one or more polymerizable monomers, oligomers, prepolymers or combinations thereof.
35. The curable composition of claim 25 wherein the curative (b) is substantially non-migratory in said carrier.
36. The curable composition of claim 25 wherein the polymer capsule comprises from about 0.8 wt. percent to about 25 wt. percent of the encapsulated cure system.
37. An adhesive or sealant composition that is capable of being preapplied to a substrate comprising:
a) an encapsulated cure system containing a curative, the encapsulated curative,
b) an encapsulated liquid curable composition, which liquid curable composition is capable of curing or polymerizing in the presence of the encapsulated curative, and
c) a binder for adhering the encapsulated components to the substrate to which they are to be applied; wherein the encapsulated cure system comprises the aforementioned encapsulated curative, an in-situ formed carrier material in which the encapsulated curative is incorporated and a polymer capsule encasing said carrier material wherein the carrier material is a natural or synthetic material or composition that is substantially non-flowing in the absence of external forces, elevated temperatures or both and is formed by the action of a curative with or on a precursor composition for said carrier material following the addition of the encapsulated curative to said precursor composition wherein either (i) the curative for the in-situ formed carrier material is different from and in addition to the encapsulated curative contained in said carrier material or (ii) the curative for the in-situ polymerized carrier material is the same as the encapsulated curative and the amount of said curative is at least 1.6 weight percent prior to the in-situ polymerization of the carrier material and at least 0.1 weight percent following the in-situ polymerization of the carrier material: weight percent being based on the weight of the carrier material said curative for the carrier precursor composition being soluble or miscible in said precursor composition.
38. The composition of claim 37 wherein the carrier material is (a) of a soft, putty-like or gel-like character or (b) a solid or semi-solid that is (i) soluble in a liquid curable matrix component of the curable composition with which they are to be used, (ii) softened by a liquid curable matrix component of the curable composition with which they are to be used, (iii) softened by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (iv) softened by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (v) is softened by the method or process by which the encapsulated curative is to be made available to other components of the curable composition with which they are to be used, (vi) rendered flowable by a liquid curable matrix component of the curable composition with which they are to be used, (vii) rendered flowable by the reaction conditions under which the curable composition with which they are to be used is cured or polymerized, (viii) rendered flowable by the environmental conditions under which the curable composition with which they are to be used is cured or polymerized, (ix) is rendered flowable by the method or process by which the encapsulated curative is to be made available to other components of the curable composition with which they are to be used.
39. The composition of claim 37 wherein the binder material is an adhesive or coating material in solution.
40. The composition of claim 37 wherein the binder is an aqueous based binder system.
41. The composition of claim 37 wherein the binder material is an actinic radiation curable composition.
42. The composition of claim 37 wherein the carrier material is of a soft putty-like or gel-like character and the precursor composition comprises a thixotropic or thickened composition of monomers, oligomers or pre-polymers, or a combination thereof, which composition is substantially non-reactive with the encapsulated curative in the encapsulated state.
43. The composition of claim 37 wherein the carrier material includes or comprises one or more thixotropic agents or one or more thixotropic or non-thixotropic gelling or thickening agents that are generated in-situ or act latently concurrent with or following encapsulation of the carrier material.
44. The composition of claim 37 wherein the carrier material is selected from the group consisting of hot melts, pressure sensitive adhesives, rubber materials, elastomer/tackifier compositions, a polymer whose Tg is less than 35° C., semi-solid and solid resins, starches and starch-based polymers, hydrogels, low temperature waxes and a thickened or gel-like mass of one or more monomers, oligomers, prepolymers or combinations thereof.
45. The composition of claim 37 wherein the carrier material is an adhesive or has latent adhesive properties.
46. The composition of claim 37 wherein the carrier material does not flow or deform except when subjected to forces of at least 1 psi.
47. The composition of claim 37 wherein the liquid curable composition is selected from the group consisting of monomers, oligomers and/or prepolymers that undergo vinyl polymerization; unsaturated polyesters; urethanes; epoxy resins; polysulfides; isocyanates; silicones; polyethers, polyurethanes and polyolefins having silanol moieties capable of undergoing silanol condensation or hydrosilation reactions; and phenoxy resins.
48. The encapsulated cure system of claim 37 wherein the precursor composition comprises one or more polymerizable monomers, oligomers, prepolymers or combinations thereof.
49. The composition of claim 37 wherein the curative (b) is substantially non-migratory in said carrier.
50. The composition of claim 37 wherein the polymer capsule comprises from about 0.8 wt. percent to about 25 wt. percent of the encapsulated cure system.